According to an existing technique for tracking items or vehicles, a device known as a radio frequency identification (RFID) tag is mounted on each item or vehicle. Signposts that transmit short-range signpost signals are provided near locations where tags will likely pass, for example near a door through which tags routinely travel. The tags can receive the signpost signals from nearby signposts, and can also transmit wireless tag signals that include information from the signpost. The tag signals typically have a an effective transmission range that is significantly longer than the effective transmission range of the signpost signals. Stationary devices commonly known as readers are provided to receive the tag signals. Existing systems of this type have been generally adequate for their intended purposes, but have not been satisfactory in all respects.